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craigr

Odd HD: 8 pending sectors > 0 pending & 0 reallocated sectors?!?

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Posted (edited)

So this is what I have after running preclear...

 

#   ATTRIBUTE                              INITIAL  CYCLE 1  STATUS                                                                  
#   5-Reallocated_Sector_Ct                 0        0        -                                                                      
#   9-Power_On_Hours                    7108     7154     Up 46                                                                
#   194-Temperature_Celsius               32       33       Up 1                                                                    
#   196-Reallocated_Event_Count          0        0        -                                                                      
#   197-Current_Pending_Sector            8        0        Down 8                                                                  
#   198-Offline_Uncorrectable                0        0        -                                                                      
#   199-UDMA_CRC_Error_Count            0        0        -                                                                      
 

I got the warning that I had a smart error on one of my WD80EFZX drives showing "197-Current_Pending_Sector 8"  so I replaced the drive and rebuilt.  I took the drive with 8 pending sectors and ran an erase and preclear on it.  After the preclear ended I now have zero pending sectors, but also 0 for reallocated event count.  I presumed that when the pending sectors were cleared that the reallocated event count would go up.   What happened to the 8 pending sectors?

 

Granted, this was the RAW value, but still... shouldn't something have changed.? The disk appears to be 100% fine according to the smart data with no reallocated sectors.

 

What gives?

 

I'm going to run three more preclears on the disc and if it passes I think I'll return it to service.  What do you all think?

 

I did a parity check a couple days before I got the smart error.  I've been using unRAID for many years and this is the first time I had anyparity sync errors that I did not expect;  got 2 parity sync errors that were "fixed."  Could it be that I did not actually have parity sync errors, but that some of the data in the 8 sectors that had been pending reallocation were what was actually bad, and not the parity?  At this point I have rebuilt the array and overwritten parity so if the pending sectors caused the error than somewhere on that disk I have some bad data...

 

Thanks,

craigr

Edited by craigr

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1 minute ago, johnnie.black said:

If the bad sectors are read successfully after a new write no reallocation is done.

Thanks.  So that would imply that that my data was good on the drive?  And also the sectors were good?  Is this drive OK?

 

This would imply that my parity was also sound when I rebuilt the drive, right?

 

Thanks again,

craigr

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Just now, craigr said:

So that would imply that that my data was good on the drive?

No, it just means that after being written again the sectors can now be read, data there earlier could not be read successfully.

 

 

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3 minutes ago, johnnie.black said:

No, it just means that after being written again the sectors can now be read, data there earlier could not be read successfully.

 

 

Strange.  Do you have any examples of why this could be the case?

 

Seems very odd to me.  Do you think this drive is OK?

 

Best,

craigr

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1 minute ago, craigr said:

Strange. 

Quite common actually.

 

2 minutes ago, craigr said:

Do you think this drive is OK?

Run a couple of extended SMART tests, or preclear postread tests, if it passes it's OK for now, though it's more likely to fail again.

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All right.  That all makes sense.

 

Thanks one more time.

 

Best regards,

craigr

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